It is well known to employ window film consisting of a thin polymeric film, particularly a polyester film, which is applied to the inside surface of a window pane, to increase the impact resistance thereof. The window film also holds broken glass fragments together when a glass sheet is broken by an impact, such as an accidentally caused impact, e.g. initiated by physical activity, a deliberately caused impact, e.g. as a result of a break-in attempt or a bomb explosion, or a natural phenomenon, e.g. a hurricane or an earthquake.
The window film is generally applied to the visible portion of the pane, and therefore the edge portions of the pane which are concealed by the window frame are not protected. When a window pane is impacted, a large force concentration is applied to the unprotected edge portions, causing the filmed pane portion to separate from the edge portions and fall inwardly into the room as a single entity. An intruder may also gain entry to the room by using a suitable implement to break the glass near the unprotected edge portions, separating the filmed pane portion from the unprotected edge portions, and squeezing between the filmed pane portion and the unprotected edge portions so as to enter the room.
To prevent injury or damage resulting from a pane that inwardly falls into the room, and to further prevent the separation of a window pane from its frame, the prior art employs various means to secure the window film to the window frame.
U.S. Pat. No. 5,992,107 discloses a tensile loading transfer strip having two load bearing flanges. A double sided foam adhesive strip is mounted on each flange such that one strip is mounted to an edge of window film adhered to a glass window pane and the second strip is mounted to an edge of a window frame.
U.S. Pat. No. 6,082,062 discloses a security attachment system includes two-sided tape that overlaps an edge portion of a film covering a glass pane and a side portion of the adjacent window frame. A hollow flange track having a right-angled cross-sectional shape is positioned over the tape, for each of the four edges whereat the frames meet the glass panes. Each flange is fastened to the window frame.
WO 02/088504 discloses an anchoring profile comprising two outer strips of substantially rigid plastic material for attachment by adhesive to the window film and the window frame, respectively, and a flexible interconnecting strip between the outer strips.
The element of each of the aforementioned prior art securing means that is adhered to both the film and the window frame is exposed to inclement weather conditions and to sunlight, and therefore will detach from the window film or from the window frame over the course of time, requiring labor intensive operations relating to the replacement of the securing means. Furthermore, the adhesive force by which the securing means is attached to the window frame is of limited strength, and the securing means is liable to fail when subjected to a relatively low impact of approximately 5-7 psi. Means of securing a window film of greater reliability and of greater strength is therefore needed.
GB 2327700 discloses a clamping profile comprising a first elongate side portion having a ribbed film contacting surface which is attached to the surrounding frame to clamp the overlapping film, a rounded edge to prevent the film from tearing under load, and a second elongate side portion having a sealing gasket for cushioning impact movement of the pane and film. In this publication, the clamping profile also reduces the amount of light that is transmitted through the window pane into the room. Furthermore, the window film is liable to be dislodged from underneath the film contacting surface when the window pane is subjected to a relatively low impulse of approximately 5-7 psi, which causes the pane to bend and to be separated from its frame.
It is an object of the present invention to provide a window film anchoring device which is adapted to prevent the separation of a pane from the frame in which it is mounted.
It is an additional object of the present invention to provide a window film anchoring device that can withstand an impact of a greater magnitude than that of the prior art.
It is an additional object of the present invention to provide a window film anchoring device that is not exposed to inclement weather conditions or to sunlight.
It is yet an additional object of the present invention to provide a window film anchoring device that can be easily attached to an existing frame.
Other objects and advantages of the invention will become apparent as the description proceeds.